1. Field of the Disclosure
This disclosure generally relates to an optical touch system and, more particularly, to an optical touch system with brightness compensation and a brightness compensation method thereof.
2. Description of the Related Art
An optical touch system generally utilizes an image sensor to capture a plurality of image frames containing a touch surface image and performs the object tracking according to the position variation of a finger image in the image frames.
For example referring to FIG. 1A, it shows a schematic diagram of the conventional optical touch system 9, which includes a touch surface 91, two image sensors 92, 92′ and a plurality of light bars 93. When the image sensors 92 and 92′ are capturing images, the light bars 93 emit light to allow the image sensors 92 and 92′ to receive the light from the light bars 93. In this manner, when a finger (not shown) is in contact with the touch surface 91, the image sensors 92 and 92′ can capture image frames containing a dark region formed by the finger blocking the light bars 93, and a processing unit (not shown) can identify the finger position according to the image frames.
However, brightness at corners of the touch surface 91 is not continuous due to the disposition angle of the light bars 93 such that the brightness distribution of the image frames captured by the image sensors 92 and 92′ is not uniform even though there is no finger touches the touch surface 91, e.g. the three dark regions d1-d3 shown in FIG. 1B. Therefore, misidentification of the finger position may occur when the processing unit performs the image processing.
Accordingly, the present disclosure further provides an optical touch system with brightness compensation and a brightness compensation method thereof that may be adjusted before shipment to allow the image sensor to capture image frames having a substantially uniform brightness distribution.